Arcbound Mamba [Unknown Event] Dark Ascension Does damage equal to half

Does damage equal to half the Defending Pokemon's remaining HP (rounded down to the nearest 10)

and all of Yavimaya is its flower

it does 40 damage to that Pokemon

You can only Special Summon "Black Luster Soldier - Super Soldier(s)" once per turn

counter it

Arcbound Mamba [Unknown Event] Dark Ascension Does damage equal to halfSet: Unknown Event Type: Artifact Creature Snake Rarity: Common Cost: {3}{G} Deathtouch Poison Modular 2 (This creature enters the battlefield with two +1 +1 counters on it. When it dies, you may put its +1 +1 counters on target players or artifact creature. If they're put on a player this way, they become poison counters.)